Notes

import UIKit


// A Tuple : Keeps More Than One Value
let person1 = (1984, "Emir", "Civaş")

let (birthDate, name, surname) = person1

print("(name) (surname) BD : (birthDate)")

// Hold {Key - Value} In Tuple
let person2 = (bd:1983, fn:"Sercan", ln:"Tuncay")
print("(person2.fn) (person2.ln) BD : (person2.bd)")


// Optional : A variable might have a value or have nil
// Optionals are shown with ?
var data: Int?
print("Data : (data)")

var ad : String? // An Optional String which may contain val

print(ad)

// Unwrap optional to get value needed
if let actualValue = ad
{
print("Unwrapped Value = (actualValue)")
}

else
{
print("ad variable is nil")
}

// Get The Value (Force)
// Error Code Is An Optional Int with Initial Value : 400
var errorCode : Int? = 400
print(errorCode);

// Instead Of Using If Block To Unwrap, Force Optional To Get
// Value
var errCodeValue = errorCode!;
print("Error Code Value : (errCodeValue)")

var userName : String?

// ? If userName is nil, Use "Not Defined"
print(userName ?? "Not Defined")